Biological Characteristics And Toxicity Determination Of Insecticide From Helopeltis Theivora Waterhouse

Hespeltis theivora Waterhouse belongs to Hemiptera,Miridae of the Miridae family,also known as Lygus tea bug,cashew horn bug,tea bug,etc.It is a variety of tropical economic crops such as cocoa,tea trees,peppers,cashews,etc.There are currently more than 60 species of important pests.The worm sucks the young tissue juice of the host and damages it.The feeding part forms a fusiform water stain or irregularly round feeding spot.After overfeeding,the wound is easy to cause a variety of diseases such as anthracnose,which seriously affects the yield of crops.So far,domestic and foreign researches on A.chinensis have focused on living habits,occurrence environment and prevention methods,and have provided some valuable reference materials.In order to better control the pest damage,establish feasible control strategies to reduce economic losses.This article discusses the developmental period of the eggs and nymphs of A.versicolor and the biological characteristics of adult emergence,mating and egg laying.The indoor toxicity determination of 9 kinds of pesticide technicals was carried out using the bean soaking method.The specific research results are as follows:1.The morphological characteristics and developmental period of Hespeltis theivora WaterhouseThrough indoor breeding of the insect,the ontogeny of Lygus teapotentus develops eggs,nymphs(1-5 instars),adults and other stages.Under indoor breeding conditions,the developmental period of each stage is: egg stage is 5-6 days,the average It is 5.53±0.51 d.The nymph stage is 11-14 days,with an average of 12.59±1.00 d.The longest female adult was 63 days and the shortest 5 days,with an average of 22.94±3.39 days.The longest male adult was 52 days and the shortest 5 days,with an average of 19.22±2.81 d days.The life span of female adults is significantly longer than that of male adults.The morphological characteristics of each instar: the eggs are white and orange-red at the beginning,and then slowly turn orange.The nymphs have no wings at the initial stage,and then the body turns green.The wings gradually grow.The adult stage body is brown or yellowish brown,and the wings are translucent and dark.The reproductive ability of A.ceratoides: single female spawning rate is 167.55±6.71,hatching rate is 71.60%±3.27%,and the spawning period is15.05±2.61 d.2.The feeding and reproductive ability of Hespeltis theivora WaterhouseThe number of eggs laid by a single female adult of Lygus teapot was 160.50±23.60(grain),ranging from 136 to 184(Table 10).The average pre-oviposition period was4.90±1.29 d,the peak period of spawning was 8.50±1.19 d,and the spawning period was15.05±2.61d(Table 10).The newly emerging adults enter the pre-oviposition stage as early as 2-3 days later,and then begin to lay eggs,and they can still lay a few eggs on the day of death.3.Determination of the virulence of 9 insecticides to Hespeltis theivora Waterhouse.Bean soaking method has 48 h virulence to L.ceratophyllum adults,from low to high:Bubuzizione <diafenthiuron <abamectin <tolfenpyrad <emamectin benzoate <acetamiprid<lambda cyhalothrin <Thiamethoxam <Lambda-cypermethrin.The lethal concentration(LC50)of the nine pesticides are: 968.477 mg/L,751.666 mg/L,519.112 mg/L,416.921mg/L,94.353 mg/L,63.996 mg/L,29.283 mg/L,15.189 mg /L,9.954 mg/L;the 72-hour virulence to the adult Lygus Lygus is buprofezinone <diafenthiuron <avermectin<tolfenpyrad <emamectin <acetamiprid <highly effective Lambda-cyhalothrin<Thiamethoxam <Lambda-cypermethrin.The lethal concentrations(LC50)of the nine pesticides are: 826.976 mg/L,624.656 mg/L,304.431 mg/L,360.602 mg/L,52.357 mg/L,58.961 mg/L,26.179 mg/L,5.752 mg /L,4.286 mg/L.